Emerald Crad quadrupled overnight?

[Bfgjose]

Hello,

New to the Bio-Reef hobby as of 1 month ago. When I got my first pair of Clowns I also got some CUC that included a few snails, hermit crabs and 1 emerald crab. Yesterday while adding some new mushrooms and securing my Arch with epoxy I noticed that the Emerald was substantially bigger...I mean the length of one arm was bigger than the body. I searched and learned emeralds molt and thought OK, but dang that a lot of growth but I never saw the old exoskeleton. The later I saw the crab move what I thought was exoskeleton and went to fish it out of tank to see the emerald still had flesh to it and in comparison the claws are 8x bigger, not exaggerating. I've concluded that this new crab we have named "Thanos", hitch-hiked in the leather shroom day before. Wanted to confirm with R2R community this is an Emerald? This big will it attack fish or disrupt soft corals? I have a yasha goby and pistol I think would be the most vulnerable. I have only seen him eat algea thus far. Attached pics of Thanos in night pick and Ozzy in color for comparison.

 

[Mr. Mojo Rising]

Yes, its an emerald. They mainly eat algae, but it can sometimes eat some polyps of some corals. They move slowly so not a threat to fish. They are generally peaceful and will leave most inverts alone. Good luck

 

[Bfgjose]

Thanks. I was able to catch him and return to store. Too anxious about him going after corals. More mindful now about how big CUC can get.

 

[jabberwock]

If it gots claws, it breaks laws. This is a crab free zone people.